Male and Female Anatomy
Puberty
Puberty begins at age 8 to 10 for most girls in the United States. It is triggered by rising levels of GnRH, stimulates anterior lobe of pituitary to produce: FSH and LH. FSH stimulates developing ovarian follicles and they begin to secrete estrogen, progesterone, inhibin, and a small amount of androgen. Thelarche is the onset of breast development is the earliest noticeable sign of puberty. Pubarche is the appearance of pubic and axillary hair, sebaceous glands, and axillary glands. Menarche is the first menstrual period, which requires about 17% body fat in teenagers and 22% in adults. Estradiol stimulates vaginal metaplasia, growth of ovaries and secondary sex organs, growth hormone secretion, responsible for feminine physique because it stimulates the deposition of fat, and makes a girl’s skin thicker. Progesterone, primarily acts on the uterus preparing it for possible pregnancy in the second half of the menstrual cycle. Estrogens and progesterone suppress FSH and LH secretion through negative feedback. Inhibin selectively suppresses FSH secretion. Hormone secretion is distinctly cyclic and the hormones are secreted in sequence.
Oogensis
Oogensis is egg development. Oogensis produces haploid gametes by means of meiosis, distinctly cyclic event that normally releases one egg each month, accompanied by cyclic changes in hormone secretion, and cyclic changes in histological structure of the ovaries and uterus. Egg development resumes in adolescence. Embryonic development of ovary: female germ cells arise from yolk sac, colonize gonadal ridges the first 5 to 6 weeks of development, differentiate into oogonia and multiply until the fifth month, transform into primary oocytes: early meiosis I, most degenerate (atresia) by the time the girl is born, egg or ovum: any stage from the primary oocyte to the time of fertilization, by puberty, 400,000 oocytes remain. FSH stimulates monthly cohorts of oocytes to complete meiosis I. Each oocyte divides into two
Puberty begins at age 8 to 10 for most girls in the United States. It is triggered by rising levels of GnRH, stimulates anterior lobe of pituitary to produce: FSH and LH. FSH stimulates developing ovarian follicles and they begin to secrete estrogen, progesterone, inhibin, and a small amount of androgen. Thelarche is the onset of breast development is the earliest noticeable sign of puberty. Pubarche is the appearance of pubic and axillary hair, sebaceous glands, and axillary glands. Menarche is the first menstrual period, which requires about 17% body fat in teenagers and 22% in adults. Estradiol stimulates vaginal metaplasia, growth of ovaries and secondary sex organs, growth hormone secretion, responsible for feminine physique because it stimulates the deposition of fat, and makes a girl’s skin thicker. Progesterone, primarily acts on the uterus preparing it for possible pregnancy in the second half of the menstrual cycle. Estrogens and progesterone suppress FSH and LH secretion through negative feedback. Inhibin selectively suppresses FSH secretion. Hormone secretion is distinctly cyclic and the hormones are secreted in sequence.
Oogensis
Oogensis is egg development. Oogensis produces haploid gametes by means of meiosis, distinctly cyclic event that normally releases one egg each month, accompanied by cyclic changes in hormone secretion, and cyclic changes in histological structure of the ovaries and uterus. Egg development resumes in adolescence. Embryonic development of ovary: female germ cells arise from yolk sac, colonize gonadal ridges the first 5 to 6 weeks of development, differentiate into oogonia and multiply until the fifth month, transform into primary oocytes: early meiosis I, most degenerate (atresia) by the time the girl is born, egg or ovum: any stage from the primary oocyte to the time of fertilization, by puberty, 400,000 oocytes remain. FSH stimulates monthly cohorts of oocytes to complete meiosis I. Each oocyte divides into two